Infective Endocarditis

-It is an endovascular infection of cardiovascular structures including cardiac valves, atrial and ventricular endocardium, large intrathoracic vessels and intracardiac foreign bodies, e.g. prosthetic valves, pacemaker leads and surgical conduits.

-It's more common in the developing countries.
-Mortality rate equals to 100% without treatment.

Aetiology- is a consequence of two abnormal factors.

1.Bacteraemia.
                       -Poor dental hygiene.
                       -I.V. drug use.
                       -Soft tissue infections.
                       -Diagnostic or therapeutic procedures:
                                                                               -dental treatment
                                                                               -intravascular cannulae
                                                                               -cardiac surgery

2.Abnromal cardiac endothelium.
                                                      -Valvular lesions.
                                                      -Septal defects.
                                                      -PDA.(patent ductus arteriosus)
*All these abnormalities promotes platelet and fibrin deposition------>infected vegetation.

*Aortic and mitral valves are the most commonly afftected in I.E. but in I.V. drug users, right-sided lesions are commoner!



Signs and Symptoms:

"FROM JANE"
F-fever
R-roths spot
O-osler's node
M-murmur

J-janeway lesion
A-anaemia
N-nail bed(splinter haemorrhages)
E-emboli.

Diagnostic Criteria: Modified Duke's Criteria

"BE FIVE PM"

Major Criteria


B : Blood culture +ve

1. Typical micro-organisms in 2 seperate cultures or
2. Persistently +ve blood cultures drawn 12 hours apart or
3. Single +ve blood culture for Coxiella burnetti

E : Endocardial involvement

1. +ve echocardiogram (vegetation, abscess or valve dehiscence) or
2. New valvular regurgitation

Minor criteria

1. Fever > 38 oC 
2. Immunologic phenomena (glomerulonephritis, Osler’s nodes, Roth’s spots, Rheumatoid factor)
3. Vascular phenomena (major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunCtival hemorrhage, Janeway lesions)
4. Echocardiography findings (suggestive but not definitive)
5. Predisposition (heart condition or IV drug user) 
6. Microbiologic evidence (Positive blood culture but not meeting major criteria)

*Definitive Diagnosis requires 2 Major  or 3 Minor + 1 Major or  5 Minor